From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AD15E2673A9; Thu, 19 Jun 2025 18:36:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750358173; cv=none; b=Tu7Z4/z5KaVgTxS5rvAa23P0i/wcBXeRMKaLgIrUBZAsbKUzAzO32A56mvaqx3vHiVwFr3zEXAskpCU2SJaFB8+r/OQMj8H3Hvh9ukUEXVNfXiYOjr3KqfM7x8221QvSpWauhD+/LdNXXKHVzSHT3Mb/mvZDT/shhnH2kttDB1U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750358173; c=relaxed/simple; bh=840kYlQBtIBzTuRYCK9lIr3LHivR6lw5teUqKnxye1U=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=V9Iupt0oSk1oaqafrOUhkYDavgPh7g7Q+KdpZF3JmGgHPxD4gVDo9myEBdwHiEgTXRb+pZjoa7ZJw5mQ0sArm43BPmZ6YBBIrH1IDbIJMAFYLyIRE/NSOjPsR+K48XBVG76eKjltoQUjmb6DTeDf3eTzCN8ss2QNENFbIN4yILg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rQwpdIDK; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="rQwpdIDK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 21FA8C4CEF0; Thu, 19 Jun 2025 18:36:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1750358173; bh=840kYlQBtIBzTuRYCK9lIr3LHivR6lw5teUqKnxye1U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rQwpdIDKorXZCCEmcC9gDf34jdNZfCzbWg3Sa2AD2DnScGZOuQTikh0cNLCrKiO69 Zg1YBPEW5repRKJBEH5seo7ppGRb2OMIYAw2m0u7sJfpiDaDsqU+YHRvwD5Nmw1F1F 1CNZNdLS9AF7pl8nChA6rR/MEDJC3CHHeLu91Ajo+spw0rZJlC1hSN183gDuV5wkwi O1/eiorO0eL1WNxQdAaJJjsZZ8cCnw4flmMwpYGvXP5tL7/fyqEkjlICmlv3+QlioJ MyVdRAOz7w1wIDp44/johcURMVlHyruhHApN3gI4TxTHMxCgDQFIfHdxC9G2y9x651 bwm09RvzfyjEg== From: SeongJae Park To: Andrew Morton Cc: SeongJae Park , damon@lists.linux.dev, kernel-team@meta.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org, #, 6.3.x Subject: [PATCH 1/2] mm/damon/sysfs-schemes: free old damon_sysfs_scheme_filter->memcg_path on write Date: Thu, 19 Jun 2025 11:36:07 -0700 Message-Id: <20250619183608.6647-2-sj@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250619183608.6647-1-sj@kernel.org> References: <20250619183608.6647-1-sj@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit memcg_path_store() assigns a newly allocated memory buffer to filter->memcg_path, without deallocating the previously allocated and assigned memory buffer. As a result, users can leak kernel memory by continuously writing a data to memcg_path DAMOS sysfs file. Fix the leak by deallocating the previously set memory buffer. Fixes: 7ee161f18b5d ("mm/damon/sysfs-schemes: implement filter directory") Cc: stable@vger.kernel.org # 6.3.x Signed-off-by: SeongJae Park --- mm/damon/sysfs-schemes.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c index 0f6c9e1fec0b..30ae7518ffbf 100644 --- a/mm/damon/sysfs-schemes.c +++ b/mm/damon/sysfs-schemes.c @@ -472,6 +472,7 @@ static ssize_t memcg_path_store(struct kobject *kobj, return -ENOMEM; strscpy(path, buf, count + 1); + kfree(filter->memcg_path); filter->memcg_path = path; return count; } -- 2.39.5